CN117236142B - Finite particle analysis method, system and medium for resolving cable rod system - Google Patents

Abstract

The application discloses a finite particle analysis method, a finite particle analysis system and a finite particle analysis medium for calculating a cable rod system, which belong to the technical field of structural power analysis and comprise the following steps: discretizing the cable rod system into a plurality of rigid bodies, wherein the rigid bodies comprise connecting units and driving units; dividing a continuous driving motion process into an unsteady time domain interval and a steady time domain interval according to the motion time domain characteristics of the cable rod system; in an unsteady time domain interval, performing kinematic positive solution calculation to obtain a displacement solution of the rigid body; in a steady-state time domain interval, carrying out static equilibrium inverse solution calculation to obtain a displacement solution of the rigid body; calculating the direction vector of the connection unit according to the displacement solution by adopting a particle method; calculating the displacement, the speed and the acceleration of the rigid body by adopting a dynamics method and combining the direction vectors; and calculating and judging whether the total kinetic energy of the system is converged or not. Aiming at the problems of poor calculation convergence and low precision of nonlinear cable-rod time domain characteristics in the prior art, the method and the device improve the calculation convergence and the calculation precision.

Description

Finite particle analysis method, system and medium for resolving cable rod system

Technical Field

The present application relates to the field of structural dynamics analysis, and more particularly, to a method, system, and medium for finite particle analysis of resolving cable systems.

Background

With the development of high-tech fields such as aerospace, aviation, ocean exploration and the like, various large-span and ultra-light cable beam structures are widely applied to engineering practice, such as solar sail structures of space stations, airfoils of hypersonic aircrafts and the like. These cable bar structures have large static deformation and dynamic deformation. In order to accurately predict and evaluate the impact of these deformations on structural performance, geometrical nonlinear effects of the component must be considered.

At present, the numerical calculation methods for solving the time domain dynamic response of the large-deformation nonlinear cable rod system mainly comprise two types: the method is a traditional linear finite element method, and the method is a nonlinear dynamic finite element method. The former has lower precision when dealing with large deformation problems, while the latter has huge calculation amount and is difficult to perform time domain analysis. Therefore, how to efficiently and accurately solve the time domain dynamic response of the large-deformation nonlinear cable-rod system is a difficult problem to be solved at present.

Chinese patent application, application number CN202011356942.5, publication day 2021, 3 and 12, discloses a method, system and storage medium for rapidly calculating structural steady-state nonlinear dynamic response, comprising: decomposing the target structure into a linear substructure and a nonlinear substructure along an interface of the linear member and the nonlinear member; applying an interactive interface force at the boundary of the linear substructure and the nonlinear substructure; calculating the response of the nonlinear substructure according to the interface force; a solution to the overall structural response is calculated. However, when the nonlinear substructure is solved by adopting an equivalent linearization method, the equivalent rigidity is difficult to accurately determine, and the calculation precision and the convergence are required to be further improved.

Disclosure of Invention

1. Technical problem to be solved

Aiming at the problem of low precision of solving the time domain characteristics of the large-deformation nonlinear cable system in the prior art, the application provides a finite particle analysis method, a finite particle analysis system and a finite particle analysis medium for solving the cable system, and the calculation precision of the time domain characteristics of the large-deformation nonlinear cable system is improved by means of non-uniform rigid body distribution under modal guidance, a steady state and non-steady state calculation method and the like.

2. Technical proposal

The aim of the application is achieved by the following technical scheme.

One aspect of embodiments of the present description provides a method of finite particle analysis of a solution cable system, comprising: discretizing the cable rod system into a plurality of rigid bodies, wherein the rigid bodies comprise connecting units and driving units; dividing a continuous driving motion process into an unsteady time domain interval and a steady time domain interval according to the motion time domain characteristics of the cable rod system; setting the initial speed of a driving unit in the acquired unsteady time domain interval, and performing kinematic positive solution calculation to obtain a displacement solution of the rigid body; setting the initial length of a driving unit in the acquired steady time domain interval, and performing static equilibrium inverse solution calculation to obtain a displacement solution of the rigid body; calculating the direction vector of the connecting unit according to the results of the kinematic solution and the static equilibrium solution by adopting a particle method; calculating the displacement, the speed and the acceleration of the rigid body by adopting a dynamics method and combining the acquired direction vector of the connecting unit; and calculating and judging whether the total kinetic energy of the system is converged or not according to the obtained displacement, speed and acceleration of the rigid body, and taking the total kinetic energy as a convergence criterion of kinematic calculation.

Further, setting the initial speed of the driving unit in the acquired unsteady time domain interval, and performing kinematic positive solution calculation to obtain a displacement solution of the rigid body comprises the following steps: setting the initial speed of a driving unit as an initial condition of kinematic solution in an unsteady time domain interval; dividing the time of the unsteady time domain interval into a plurality of time steps, and calculating the driving displacement of the driving unit according to the set initial speed in each time step; calculating the internal force of the driving unit in the current time step according to the driving displacement of the driving unit in the current time step and according to the internal force displacement relation in the pre-established rigidity matrix of the driving unit; integrating unbalanced forces born by the rigid bodies in the current time step according to the internal forces calculated by the connecting units in the current time step; calculating the displacement, the speed and the acceleration of each rigid body in the current time step by adopting a central difference method according to the unbalanced force of each rigid body in the current time step; calculating the kinetic energy of the rigid body and the total kinetic energy of the system according to the speed of each rigid body in the current time step; judging whether the total kinetic energy of the system meets a preset convergence condition, if not, entering the next time step to continue iterative computation until the convergence condition is met.

Further, according to the driving displacement of the driving unit in the current time step and according to the internal force displacement relation in the pre-established driving unit stiffness matrix, calculating the internal force of the driving unit in the current time step comprises the following steps: establishing a local coordinate system between two end point rigid bodies of the driving unit; under the established local coordinate system, calculating the axial strain of the driving unit at the current time step by utilizing the axial strain and axial displacement relation of the driving unit according to the material parameters, the section parameters and the driving displacement of the end point rigid body at the current time step of the driving unit; the axial strain of the driving unit is brought into a one-dimensional constitutive equation of the material, and the axial stress of the driving unit at the current time step is calculated; according to the sectional area of the driving unit, converting the axial stress into the axial tensile force applied to the driving unit at the current time step, namely the internal force of the driving unit; the calculated internal force of the drive unit is stored in a scalar matrix of force values.

Further, by adopting a dynamics method and combining the obtained direction vectors of the connecting units, calculating the displacement, the speed and the acceleration of the rigid body comprises the following steps: establishing a differential equation representing the motion of each rigid body by applying an explicit central differential format; substituting the unbalanced force of each rigid body in the current time step into a differential equation; assuming an initial displacement and velocity of each rigid body at a current time step; solving a differential equation to calculate the displacement, the speed and the acceleration of each rigid body at the current time step; judging whether the calculation result of each rigid body displacement is smaller than a preset displacement tolerance, and judging whether the calculation result of each rigid body speed is smaller than a preset speed tolerance; if the displacement or the speed does not meet the respective tolerance requirement, updating the initial displacement of each rigid body by adopting the calculated displacement, updating the initial speed of each rigid body by adopting the calculated speed, and returning to the step of solving the difference equation to continue iterative calculation; if the displacement and the speed meet the tolerance requirements, recording the displacement, the speed and the acceleration of each rigid body in the current time step; and calculating the total kinetic energy of the system according to the speed of each rigid body, and carrying out kinetic energy convergence judgment.

Further, setting the initial length of the driving unit in the acquired steady state time domain interval, and performing static equilibrium inverse solution calculation to obtain a displacement solution of the rigid body comprises the following steps: setting the initial length of a driving unit as an initial condition for static balance calculation in a steady-state time domain interval; dividing the steady-state time domain interval into a plurality of time steps, and calculating displacement, speed and acceleration in each time step; calculating the total kinetic energy of the system according to the speed obtained by iterative calculation of each rigid body in the current time step; judging whether the total kinetic energy of the system reaches a preset convergence tolerance; continuously judging the difference between the total system kinetic energy of the current time step and the total system kinetic energy of the last time step; and when the total kinetic energy of the system does not reach the set tolerance and is larger than the previous time step value, entering the next time step to continue the static balance iterative calculation.

Further, dividing the steady state time domain interval into a plurality of time steps, calculating the displacement, velocity and acceleration in each time step comprises the steps of: calculating the displacement of the driving unit in the current time step according to the set initial length; bringing the displacement of the driving unit into an internal force displacement relation equation of each connecting unit, and calculating the internal force of each connecting unit in the current time step; substituting the internal force of each connecting unit into a dynamic equation, and adopting a central difference method to iteratively calculate the displacement, the speed and the acceleration of each rigid body in the current time step.

Further, discretizing the cable system into a plurality of rigid bodies comprises the steps of: according to the stress state of the cable rod, acquiring the front N-order vibration modes of the cable rod by adopting a modal analysis method, and generating each-order vibration mode curve; densely distributing rigid bodies at the wave crest and the wave trough of each order of vibration mode curve by adopting a distance smaller than the minimum distance between adjacent rigid bodies; adopting a spacing dispersion distribution rigid body larger than the maximum distance between adjacent rigid bodies in the waveform straight section of each order vibration mode curve; setting the distance between adjacent rigid bodies, and setting the minimum distance between the rigid bodies at the position with the maximum curvature of each order vibration mode curve; at the minimum curvature, the rigid body spacing is set to be the maximum.

Further, a connection unit between the rigid bodies is provided, the connection unit comprising: the rigid beam unit is connected with the rigid body without rotation constraint release, the rigid two-force rod unit is connected with the rigid body without rotation constraint release, and the rigid linear cable unit and the curve cable unit are connected with the rigid body between the cable rods; the curve cable unit is a parabolic cable unit or a catenary cable unit; the initial speed of the driving unit is a constant speed or a variable speed; the constant speed represents that the initial speed of the driving unit in the unsteady state time domain interval is kept unchanged; the variable speed means that the initial speed of the drive unit in the unsteady time-domain interval changes with time.

Another aspect of embodiments of the present disclosure also provides a system for finite particle analysis methods based on resolving a cable system of the present application, comprising: the rigid body discrete module is used for dispersing the cable rod system into a rigid body according to modal analysis; the connecting unit definition module is used for setting connecting units and driving units between the rigid bodies; the time domain interval dividing module is used for dividing a continuous driving motion process of the cable rod system into an unsteady time domain interval and a steady time domain interval; the unsteady state time domain calculation module is used for carrying out kinematic positive solution calculation in an unsteady state time domain interval; the steady-state time domain calculation module is used for carrying out static balance inverse calculation in a steady-state time domain interval; the direction vector calculation module calculates the direction vector of the connecting unit by adopting the rigid coordinate position; the dynamic equation solving module generates a dynamic equation according to the topological relation of the cable rod system, brings the direction vector of the connecting unit into the dynamic equation, and adopts a central difference method to iteratively solve the motion parameters of each rigid body; and the convergence judging module is used for judging whether the total kinetic energy of the system meets the convergence condition according to the kinematic calculation result of the rigid body.

Another aspect of embodiments of the present disclosure also provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement a method of finite particle analysis of a solution cable system of the present application.

3. Advantageous effects

Compared with the prior art, the advantage of this application lies in:

(1) By adopting the non-uniform discrete distribution method of the rigid body under the guidance of modal analysis, the rigid body can be concentrated in a large deformation area of the cable rod, the calculation nodes of the key parts are increased, and the capturing precision of the deformation effect is improved. Different calculation methods are respectively adopted for distinguishing the steady state and the unsteady state, so that error accumulation of the traditional linear method in the whole time domain is avoided, and the calculation accuracy of the whole time domain process is improved;

(2) Setting various connecting units such as a rigid beam unit, a two-force rod unit, a non-rigid cable unit and the like, wherein the various connecting units reflect the characteristics of actual components to the greatest extent, and the rigidity matrix of the driving unit considers the actual loading characteristics, so that the numerical model is closer to an actual engineering system, the calculation result is closer to the actual, and the calculation precision is improved;

(3) The driving internal force is accurately calculated by adopting the rigidity matrix of the driving unit, and then a dynamic equation is input, so that calculation errors caused by a simplified driving model are avoided; the explicit central difference method is adopted to carry out iterative solution on rigid body kinematics, so that the convergence of a nonlinear equation set is ensured, the divergence problem of the traditional linear solution is avoided, and the calculation accuracy is improved.

Drawings

FIG. 1 is a schematic diagram of the overall system architecture of the present application;

fig. 2 is a functional logic diagram of the present application.

Detailed Description

The present application is described in detail below with reference to the attached drawing figures and specific examples.

Fig. 1 is a schematic diagram of an overall system structure of the present application, and as shown in fig. 1, the method for analyzing finite mass points of a cable system includes the following technical steps:

for the kinematic mechanical numerical simulation analysis of a quasi-static system, in order to accelerate the resolving speed of the whole system, the unsteady state and the steady state time domain interval range of the cable rod system in the continuous driving motion process can be distinguished, and a plurality of stage steps in the steady state time domain range can be determined if necessary.

And establishing an initial limited rigid body model of the cable rod system, wherein the cable rod system is discretized into rigid bodies, the system is discretized into a group of rigid body collection in space, and the rigid bodies are connected by adopting units, and the units have no mass and only bear internal force.

Specifically, according to the stress state of the cable rod, acquiring the front N-order vibration modes of the cable rod by adopting a modal analysis method, and generating each-order vibration mode curve; applying stress representing actual working conditions and boundary conditions to the static cable rod system; carrying out modal analysis on a cable rod continuous system meeting boundary conditions based on numerical methods such as a finite element method and the like; solving the self-vibration characteristics of the cable rod through modal analysis to obtain the front N-order self-vibration modes; drawing the mode shape corresponding to each order mode as a vibration mode curve; recording characteristic parameters of each order of vibration mode curve, including kinematic distribution, deformation degree and the like; the first N-order vibration mode curves are sequentially selected according to importance, wherein the low-order vibration mode determines the main characteristic of the cable pole movement. In the application, a finite element model of a quasi-static cable rod system is constructed, and actual boundary conditions and stress loads are applied; a maximum mode analysis order Nmax is pre-designated, and the value is generally 10 to 20; performing modal analysis from 1 order to Nmax order successively to obtain the vibration mode and frequency corresponding to each order; analyzing the motion characteristics of each order of vibration modes, and judging whether the kinematic contribution degree is obviously attenuated; when the characteristics of the high-order vibration mode are no longer obvious, taking the previous order as the vibration mode order N which is actually needed; repeating the above process until the representative vibration mode order N under different stress conditions is obtained. Through the method and the device, the reasonable modal analysis order N can be determined according to specific stress conditions, unimportant high-order vibration modes are filtered, unnecessary calculated amount is avoided, and efficiency of obtaining vibration mode curves is improved.

Densely distributing rigid bodies at the wave crest and the wave trough of each order of vibration mode curve by adopting a distance smaller than the minimum distance between adjacent rigid bodies; in the method, all local maximum value points and local minimum value points on the vibration mode curve are detected and used as wave crest and wave trough characteristic points; taking a small parameter around each feature point, such as [ xi-delta, xi+delta ], delta. Setting the distribution interval of the rigid bodies to be 50% -80% of the minimum distance between the adjacent rigid bodies in the cell; the distribution function of sinusoidal modulation is adopted, so that the density of rigid body distribution at two ends of the interval is moderate, and the middle is the most dense; overlapping cells near the wave crest and the wave trough, and taking a smaller distance between the rigid bodies in the overlapping area; adjusting delta value and distribution function, optimizing rigid body distribution, and enabling rigid body distribution at wave crest and wave trough to be dense enough; calculating kinematic parameters at the rigid body, and verifying the validity of dense distribution; and (5) performing iterative optimization until the precision requirement is met. According to the method and the device, the calculation accuracy of the wave crest, the wave trough and other characteristics can be improved, and the kinematic characteristics of the vibration mode curve can be reflected more accurately.

Adopting a spacing dispersion distribution rigid body larger than the maximum distance between adjacent rigid bodies in the waveform straight section of each order vibration mode curve; setting the distance between adjacent rigid bodies, and setting the minimum distance between the rigid bodies at the position with the maximum curvature of each order vibration mode curve; setting the maximum rigid body spacing at the position with the minimum curvature; detecting all straight sections with curvature smaller than a threshold value on the vibration mode curve, wherein the sections can be regarded as waveform flatness; the maximum distance Lmax between adjacent rigid bodies on these straight sections is calculated. On the straight section, setting the space between the rigid bodies to 120% -150% of Lmax, and obtaining the distribution with moderate density; adopting a linear distribution function to enable the rigid bodies to be slightly dense at the two ends of the section and to be more sparse in the middle; properly reducing the space between the rigid bodies at the two ends of the straight section to obtain smooth transition; calculating kinematic parameters of the rigid body on the straight section, and verifying the effectiveness of evacuation distribution; and iteratively adjusting the rigid body distribution until the calculation accuracy requirement is met. The setting mode of the evacuation distribution can reduce the number of rigid bodies of the straight section, improve the calculation efficiency, and ensure the precision of the end points at the same time, thereby realizing the optimization of the rigid body distribution on the whole vibration mode curve.

In summary, the method and the device can unevenly distribute the rigid bodies according to the dynamic characteristics of the cable rods, enable the rigid bodies to be gathered at the positions with severe kinematic changes, enhance the calculation precision of the positions, realize the efficient and accurate description of the kinematic characteristics of the alignment static cable rod system, and lay a foundation for subsequent simulation calculation.

Setting a connecting unit between the rigid bodies, wherein the connecting unit comprises: the rigid beam unit is connected with the rigid body without rotation constraint release, the rigid two-force rod unit is connected with the rigid body without rotation constraint release, and the rigid linear cable unit and the curve cable unit are connected with the rigid body between the cable rods; setting a unit for connecting adjacent rigid bodies in the established discrete rigid body model; the units can be a rigid beam unit, a rigid two-force rod unit and a rigid cable-free unit; the rigid beam units are used for connecting adjacent rigid bodies and are not allowed to rotate relatively; the rigid two-force rod unit is used for connecting adjacent rigid bodies constrained by relative rotation; the rigid-cable-free unit is used for connecting rigid bodies among different cable rods and allowing relative sliding to occur; the rigid cable-free unit can be realized by selecting a straight cable or a curve cable; during modeling, selecting corresponding types of units for connection according to motion constraint conditions between adjacent rigid bodies; and after the units are connected, an integral finite element model consisting of a rigid body and the units is formed. In summary, the cable-rod system finite element model which accurately reflects the motion constraint condition of each rigid body is established by arranging three types of units to connect discrete rigid bodies, and a foundation is provided for subsequent kinematic simulation calculation.

The rod units among the rigid bodies adopt beam units when the end points are free from rotation constraint, otherwise adopt two-force rod units with hinged ends; setting a unit for connecting adjacent rigid bodies in the established discrete rigid body model; the units are divided into a rigid beam unit and a rigid two-force rod unit; when the relative rotation is not allowed to occur between the adjacent rigid bodies, the rigid beam units are adopted for connection; the two ends of the rigid beam unit are rigidly connected with the adjacent rigid bodies and are not allowed to rotate; when the relative rotation is allowed to occur between the adjacent rigid bodies, the rigid two-force rod units are adopted for connection; two ends of the rigid two-force rod unit are connected with the adjacent rigid body through hinges, and rotation is allowed; according to the rotation constraint condition between adjacent rigid bodies, selecting a beam unit or a two-force rod unit for connection; accurately representing the motion constraint relation between rigid bodies through the correct selection and connection of the two rigid units; and after the units are connected, an integral finite element model consisting of a rigid body and the units is formed. The method and the device can distinguish different motion constraint conditions, select proper units for connection, and establish an accurate and reliable quasi-static cable pole system model.

Setting rigid-cable-free units for connecting rigid bodies among different cable rods in the established discrete rigid body model; the cable unit can select two-node linear cable units or curve cable units; the curve cable unit can adopt a two-node parabolic cable unit, a two-node catenary cable unit, a multi-broken cable unit or a multi-node curve cable unit; in the traction installation stage, the system is in a low-stress suspension state, and high-precision curve cable units such as two-node parabolas, catenaries and the like are preferably selected; in the stretch forming stage, the system is in a high stress state, and a simplified two-node linear cable unit can be selected; determining the type of the adopted specific cable unit according to the calculation precision requirement; the curve cable unit can more accurately represent the deformation of the rigid cable rod; the calculation of the linear cable unit is simplified; and selecting proper cable units to connect the rigid bodies according to the precision requirements at different stages. According to the method and the device, different types of cable units can be selected for connection according to the working stage and the calculation precision requirement of the system, and a quasi-static cable rod system model with both precision and efficiency is established.

Specifically, the curve cable unit is a parabolic cable unit or a catenary cable unit; in the established discrete rigid body model, a rigid curve-free cable unit for connecting rigid bodies among different cable rods is required to be arranged; the curve cable unit can be a parabolic cable unit or a catenary cable unit; the parabolic cable unit adopts parabolas to represent the geometric shape between two nodes of the curved cable; the catenary cue unit adopts a catenary equation to represent the geometric shape between two nodes of the curved cue; according to the actual working state of the rigid-free cable rod, selecting a curve form in which a parabola or a catenary can be matched with the deformation of the rigid-free cable rod; when the cable rod is in a smaller deformation state, a parabolic cable unit can be adopted; when the cable rod is subjected to larger deformation, a catenary cable unit is preferably selected; selecting a proper one of the parabolic cable unit and the catenary cable unit as a curve cable unit according to the specific working state of the cable rod; the curved cable units are connected to form a discrete rigid body model for accurately describing the geometry of the rigid-free cable rod. According to the method, the curve cable unit capable of matching with the deformation of the actual cable rod is established through two curve forms of the parabola and the catenary, and the kinematic characteristics of the quasi-static cable rod system are accurately described.

Specifically, the initial speed of the driving unit is a constant speed or a variable speed; the constant speed represents that the initial speed of the driving unit in the unsteady state time domain interval is kept unchanged; the variable speed means that the initial speed of the driving unit in the unsteady time domain interval is changed with time; in an initial dynamic model of a quasi-static cable pole system, setting an initial speed of a driving unit is required; the initial speed of the driving unit may be set in two forms of a constant speed or a variable speed; when the initial speed of the driving unit is set to be a constant speed, the initial speed of the driving unit is kept unchanged in an unsteady time domain interval; when the initial speed of the driving unit is set to a variable speed, it means that the initial speed of the driving unit is changed with time in an unsteady time domain section; according to the actual working condition of the driving unit, one of two setting modes of constant initial speed or variable speed is selected; the constant initial speed setting is simple and visual, and the variable speed setting can more accurately represent the driving characteristic; after the initial speed is set, a quasi-static cable pole system dynamics model which fully reflects the working condition of the driving unit is formed. The method can set a proper initial speed form according to different actual working conditions of the driving unit, establish a reasonable and accurate system dynamics model and provide a basis for subsequent simulation calculation.

FIG. 2 is a functional logic diagram of the present application, as shown in FIG. 2, distinguishing between an unsteady time domain interval and a steady time domain interval of a system in time to analyze a dynamic process of the system; an initial finite rigid body model is established, and the model can be directly established according to the configuration of the formed state required by design; firstly, carrying out morphological analysis on an initial model to determine the unit internal force of a member in a formed state; in an unsteady state interval, solving a system motion process to obtain parameters such as motion configuration, speed, acceleration and the like of the component; in a steady-state interval, solving a static equilibrium state of the system to obtain parameters such as configuration, internal force, rigidity and the like of the component; synthesizing the results of the unsteady motion process and the steady balance solution to generate a motion animation and a digital image of the system; adjusting initial model data according to the generated result, and repeatedly solving until the precision requirement is met; and finally, outputting a simulation result for accurately describing the system motion characteristics. According to the method, the steady-state process and the unsteady-state process are solved in stages, the model is optimized in an iteration mode, the kinematic mechanical numerical simulation of the quasi-static cable-rod system can be efficiently and accurately carried out, animation and image results are generated, and support is provided for system optimization.

After morphological analysis, obtaining an internal force result of each component unit; disconnecting the boundary member nodes, separating adjacent constraint boundary nodes or cells; after node constraint is canceled, each component unit is freely stretched and deformed under the action of self internal force; stretching each unit to an unstressed state with zero internal force as an initial state; according to the needs of the simulation forming process, a driving unit is properly added on the initial form of spreading; the driving unit is used for applying driving force to the system in the subsequent forming simulation process; finally, the initial morphological model which is stretched to a zero stress state under the action of self internal force is obtained. According to the method, the initial stress-free form is obtained through internal force driving of the component, and the driving unit is added, so that a reasonable initial form model is provided for the follow-up accurate simulation forming process, and the accuracy of simulation calculation is improved.

Setting a solution parameter and a convergence tolerance. Determining a damping coefficient: when the numerical simulation of the quasi-static cable pole system is carried out, the damping force of the rigid body needs to be set; when static balance solution is carried out in a steady time domain interval range, damping force can be set in a dummy mode or not; when carrying out the operation calculation in the unsteady state time domain interval range, the damping force of the rigid body needs to be set; adopting Rayleigh damping to construct damping force of the rigid body, namely proportional to the mass of the rigid body and proportional to the speed of the rigid body; constructing a uniform and evenly distributed Rayleigh damping force to reasonably represent the damping characteristic of the system; determining Rayleigh damping coefficient, which can be determined by harmonic response test or using empirical value; the reasonable damping force is set, so that the numerical calculation of the unsteady state movement process can be effectively stabilized. According to the time domain interval, different damping force setting strategies are adopted, so that simulation calculation is more reasonable and effective.

Flow resistance coefficient: the resistance coefficient of the air flow field can be set according to the requirement; the flow resistance coefficient reflects the fluid resistance effect of the aircraft when encountering a flow; for more complex shapes, the flow resistance coefficient under each attack angle is required to be obtained through wind tunnel tests; for simplified profiles, reference may be made to empirical values of typical flow resistance coefficients; variable flow resistance coefficients can also be set, and different flow states can be simulated by adjusting parameters; the flow resistance coefficient directly influences the calculation result of aerodynamic force; by setting the flow resistance coefficient matched with the flow field, the accuracy of aerodynamic force calculation can be improved.

The time step determines the accuracy and stability of the analysis calculation; determining a time step according to the object of the motion analysis; the time step needs to be less than the critical time step for system motion; the critical time step may be determined by simplified model pre-analysis; the proper interval of the time step can be judged through multiple trial calculations; typically, one tenth of the critical time step is taken as the analysis time step; too large a time step may result in unstable calculation divergence; too small a time step would greatly increase the computational effort; the reasonable value time step ensures the calculation accuracy and improves the calculation efficiency.

Total duration or (total steps) are analyzed: the total length of time (total number of steps) of the formation is determined based on the traction or drive speed. The total length of the forming zone can be calculated based on the stretch or compression of the material in the forming zone. The length is then divided by the draw speed to give the total length of time for formation. If step forming is employed, the total number of steps and the displacement distance per step for the entire forming stroke need to be determined. Then the total number of steps is equal to the stroke length divided by the single step displacement. After the total duration or the total steps are obtained, auxiliary processes such as heating, cooling and the like are matched in the forming process, and then continuous forming of the material can be completed.

Setting the initial speed of the driving unit in the acquired unsteady time domain interval, and performing kinematic positive solution calculation to obtain a displacement solution of the rigid body comprises the following steps:

setting the initial speed of the driving unit in the obtained unsteady time domain interval; dividing the time of the non-steady-state interval into a plurality of time steps; calculating the driving displacement of the driving unit according to the set initial speed in each time step; calculating displacement response of each rigid body according to the time step sequence by adopting a kinematic positive solution; the positive solution calculation process follows a motion equation, and fully considers the motion constraint between rigid bodies; calculating to obtain displacement solutions of the rigid bodies in each time step; repeating the calculation process to finally obtain a motion displacement solution of the rigid body in the whole unsteady state time domain interval; and obtaining displacement response of each rigid body through positive solution operation according to the initial speed condition of the driving unit. The method and the device reasonably set the initial speed and the time step, and can effectively acquire the kinematic displacement solution of the quasi-static cable pole in the unsteady state interval by adopting a stepping forward solution algorithm.

Calculating the internal force response of the driving unit according to the driving displacement of the driving unit at the current time step; establishing a local coordinate system between two end point rigid bodies of the driving unit; calculating axial strain according to the material parameters, the section parameters and the end point rigid body driving displacement of the driving unit; carrying out axial strain into a material constitutive equation, and calculating axial stress; according to the sectional area, converting the axial stress into axial tension, namely the internal force of the driving unit; storing the calculated internal force of the driving unit in a force scalar matrix; the internal force of the driving unit is used as an integrated item of unbalanced force in a subsequent rigid body method; and acquiring the internal force response of the driving unit at each moment through the local coordinate system conversion and constitutive relation. The method and the device reasonably utilize the constitutive relation of materials, calculate the internal force change of the driving unit in the motion process, and provide a key driving force source for the kinetic force analysis of the quasi-static cable-stayed system. The material of the driving unit is generally metal, and a linear elastic constitutive relation can be adopted; the one-dimensional constitutive equation expresses the relationship between the axial strain and the axial stress of the material; for linear elastic materials, the one-dimensional constitutive equation is:wherein σ is the axial stress; epsilon is the axial strain; e is Young's modulus; substituting the axial strain epsilon of the driving unit calculated in the step into the equation; one-dimensional constitutive equation containing material parameter E Calculating the axial stress sigma of the driving unit at the current moment; the internal force of the driving unit is accurately calculated by converting the strain into stress through a one-dimensional constitutive relation. In conclusion, the one-dimensional constitutive equation is combined with material parameters, so that the axial stress can be calculated according to the axial strain, and the method is a basis for accurately acquiring the internal force of the driving unit.

According to the sectional area of the driving unit, converting the axial stress into the axial tensile force applied to the driving unit at the current time step, namely the internal force of the driving unit; the unbalanced force is derived from the internal force of the driving unit and the internal force of each connecting unit; storing the calculated internal force of the driving unit in a force scalar matrix; among these, there are two sources of imbalance forces: the internal force driving unit of the driving unit is a power source for applying external force to the cable rod system, so that the internal force is a source of unbalanced force. In the solving process, the internal force of the driving unit is required to be calculated according to the motion parameters of the driving unit, and the internal force is used as a part of unbalanced force to be added into the solving process of a dynamics equation; force coupling units within the coupling units are used to describe rigid or flexible constraining relationships between rigid bodies. When the rigid body moves, the connection unit generates an internal force, which also becomes a component of the unbalanced force of the rigid body. The force in the connection unit needs to be obtained by iterative calculation. In the calculation process, the internal force of the driving unit is first solved. The forces in the drive unit are then stored in a scalar matrix of forces, which are taken as known quantities into the solution of the kinetic equation. The force in the connection unit is obtained by iterative calculation.

In summary, the unbalanced forces are derived from both the forces in the drive unit and the forces in the coupling unit. The internal force of the driving unit is stored in the matrix as a known quantity, and the internal force of the connecting unit is combined for iterative calculation, so that the unbalanced force of the rigid body can be solved, and the dynamic response of the whole cable rod system is further solved. The method has clear calculation flow and stable numerical value, and can effectively improve the calculation accuracy of the time domain characteristics of the large-deformation nonlinear cable-rod system.

According to the internal force of the connecting unit at the current moment, assembling a matrix by utilizing a rigid body method to integrate unbalanced force of each rigid body; according to the internal force of the connecting unit at the current moment, the unbalanced force of each rigid body is integrated by utilizing the rigid body method assembly matrix, and the internal force of each connecting unit at each moment needs to be solved in the calculation process. These internal forces act on the two rigid bodies that are connected to provide unbalanced forces to the two rigid bodies. The specific method comprises the following steps: according to the internal force obtained by iterative calculation of the connecting unit at the current moment, the force vector applied by the connecting unit to the two rigid bodies connected with the connecting unit can be determined. And then, assembling the matrix of the forces according to the topological relation among the rigid bodies by utilizing the idea of a rigid body method. And (5) superposing the internal force contributions of all the connecting units to obtain the unbalanced force of each rigid body at the current moment. The method avoids modeling of an independent rigid body motion equation, adopts a matrix integration thought, and is beneficial to improving the calculation efficiency. Meanwhile, the basic thought of describing the motion by the rigid body method is reserved, and the calculation result is accurate and reliable. Through the matrix assembly process of the unbalanced force of the rigid bodies contributed by the internal force of the connecting unit, the resultant force of each rigid body can be efficiently generated, and necessary input information is provided for the subsequent solution of the dynamic equation set.

The unbalanced force vector comprises component force of each rigid body under a local coordinate system; the axial tension of the rigid body acting on the end point of the driving unit is the unbalanced force of the rigid body; the internal force of the connecting unit is converted into unbalanced force of the end point rigid body through a rigid body method; summarizing unbalanced forces of the rigid bodies and constructing a system overall unbalanced force vector; the unbalanced force vector is used as a known load of a rigid motion equation to solve the rigid motion response. The dynamic load of the rigid body is accurately integrated by vector superposition of unbalanced forces of different sources, which is the key of kinematic simulation.

Calculating the displacement, the speed and the acceleration of each rigid body in the current time step by adopting a central difference method according to the unbalanced force of each rigid body in the current time step; specifically, an explicit central differential format is applied to establish a differential equation representing rigid body motion; more specifically, in the solution of rigid motion differential equations of a quasi-static cable pole system, the application of the explicit central differential format is as follows: explicit differential format: solving the variable at the current moment is only related to the variable at the previous moment; central differential format: the differentiation is approximated using the intermediate point of the previous time instant and the current time instant. The second-order central difference format is adopted to discrete the rigid motion equation:

Where a is the rigid acceleration, v is the rigid velocity, x is the rigid displacement,is the time step; the center difference makes the truncation error +.>The precision is higher than that of forward differential and backward differential; explicit differential solution is simple and direct, avoiding constructing and solving a linear equation set. In conclusion, the motion differential equation of the rigid body can be effectively solved by adopting the explicit central differential format.

Substituting unbalanced force of each rigid body at the current moment into a differential equation; assuming initial displacement and speed of each rigid body at the current moment; solving a differential equation, and calculating the displacement, the speed and the acceleration of each rigid body; judging whether the displacement is smaller than a preset displacement tolerance or not, and judging whether the speed is smaller than a preset speed tolerance or not; in the present application, the displacement tolerance may be set to a small value, for example, to one thousandth of the initial displacement of the rigid body; the speed tolerance may be set to a small value, for example to one percent of the maximum speed of the rigid body; smaller displacement tolerance and speed tolerance can be set according to the precision requirement of simulation calculation; if high precision is required, smaller tolerances, such as displacement tolerances of one ten thousandth and speed tolerances of one thousandth, can be set; if high precision is not required, larger tolerance can be set to improve the calculation speed; the specific numerical value is required to be determined according to the scale and the computing power of the simulation model; too large tolerance setting can affect the calculation accuracy, and too small tolerance setting can increase the calculation amount; through repeated experiments, proper displacement tolerance and speed tolerance values are selected; the tolerance setting is reasonable, so that the simulation calculation is efficient and accurate. By properly setting the displacement tolerance and the speed tolerance according to the precision requirement, the iterative solution of the rigid motion equation can be stable and efficient.

If the tolerance requirement is not met, updating the initial displacement and the speed according to the calculation result, and returning to the parameter setting step; if the tolerance requirement is met, recording the displacement, the speed and the acceleration of each rigid body; according to the total kinetic energy of the speed computing system, performing kinetic energy convergence judgment; and repeating the solving step to solve the rigid motion response in each time step. By iteratively solving the differential equation and checking the tolerance, the dynamic response of the quasi-static cable rod at each moment can be effectively obtained, and a basis is provided for system dynamics simulation calculation.

In each time step, calculating the speed according to each rigid body to obtain the kinetic energy of each rigid body; summing the kinetic energy of all the rigid bodies to obtain the total kinetic energy of the quasi-static cable-stayed system at the current moment; presetting a kinetic energy convergence condition, for example, the total kinetic energy variation is smaller than a certain error value; judging whether the total kinetic energy of the system at the current moment meets a convergence condition or not; if the convergence condition is met, the system tends to be stable, and the kinematic solution at the current moment is the solved; if the condition is not met, entering the next time step, and repeating the calculation of the kinematic solution; repeatedly judging the total kinetic energy convergence condition until the convergence condition is met, and ending the iteration; and finally obtaining the kinematic numerical solution of the quasi-static cable pole system meeting the kinetic energy convergence condition. According to the method, the stability of iterative solution is judged through the kinetic energy convergence condition, divergence is avoided, and accuracy and effectiveness of quasi-static cable rod kinematic calculation are ensured.

Setting the initial length of the driving unit in the acquired steady time domain interval, and performing static equilibrium inverse solution calculation to obtain a displacement solution of the rigid body comprises the following steps: setting the initial length of the driving unit in the obtained steady-state time domain interval; the length of the driving unit is used as an initial condition for carrying out static balance inverse solution in a steady-state interval;

the technical scheme for setting the initial value of the length of the driving unit is as follows: measuring and recording the length of each driving unit according to the final state shape of the unsteady state kinematic positive solution; taking the recorded length of the driving unit as the initial length of the inverse solution of the steady-state interval; thus, the configuration obtained by the steady-state inverse solution is matched with the final configuration of the unsteady-state kinematic forward solution; in the present application, the time domain section is divided into an unsteady state section and a steady state section. Different calculation ideas are adopted in the two intervals. The non-steady state interval is subjected to forward motion calculation, so that a motion track of the system under continuous driving can be obtained. At the final state of the forward solution, the length of each driving unit is measured and recorded. Then in the subsequent steady-state interval inverse solution, the recorded drive unit length is input as the initial length. And performing static balance iterative calculation. In the present application, the result of the solution in the steady-state section can be matched with the final state of the positive solution in the non-steady-state section. And the system configuration and the internal force distribution obtained by the two-interval calculation are kept consistent. This avoids the problem of mismatch between the non-steady state forward solution and the steady state inverse solution. The continuity and the accuracy of calculation are improved, and the large deformation motion rule of the cable rod system can be comprehensively and accurately reproduced. Thereby realizing the continuous transition of the configuration of the system between the final state of unsteady state movement and the steady state equilibrium state; and setting the initial length of the driving unit, and performing steady-state inverse solution operation to obtain the potential solution of the quasi-static cable pole in a steady state. The method adopts the initial value of the final state length of the unsteady state to realize the configuration anastomosis of the steady state solution and the unsteady state solution, so that the configuration of the system is continuously consistent in the whole quasi-static process.

Dividing the steady-state time domain interval into a plurality of time steps; calculating the displacement of the driving unit according to the initial length of the driving unit in each time step; carrying the displacement of the driving unit into the force-displacement relation in the connecting unit, and calculating the internal force of the connecting unit; substituting the internal force of the connecting unit into a dynamics equation; adopting a central differential format to iteratively solve the rigid body displacement, the speed and the acceleration; the application of the central differential format avoids the construction and the solution of a linear equation set; the central differential format can directly establish a motion differential equation of the rigid body, and can directly and iteratively solve the displacement, the speed and the acceleration of the rigid body at the current moment according to the information of the external force, the displacement, the speed and the like of the rigid body at the current moment. Unlike traditional motion equation set methods, the central differential format avoids the need to construct and solve the linear equation set for the entire system. The kinematic parameters of the rigid bodies are calculated step by step in an iterative manner according to the motion constraint relation among the rigid bodies. The thinking calculation process is simple and direct, and meanwhile numerical error accumulation in the solution of the linear equation set is avoided. And the calculation precision and efficiency are improved. The central differential format is combined with the idea of describing the motion state of the system by a rigid body method, so that the method can efficiently and quickly simulate the large deformation dynamic response process of the cable rod system.

By displacement driving, recursively calculating rigid body kinematic response at each moment; finally, the potential solution of the quasi-static cable pole in the steady state time domain is obtained; and solving a static equilibrium equation under a steady state by means of a central differential iteration method. The method reasonably utilizes a central differential format, solves the steady-state configuration based on displacement driving iteration, and enables the steady-state calculation process of the quasi-static cable-pole system to be stable and efficient.

Iteratively calculating the speed response of each rigid body in each time step of the steady-state time domain; the kinetic energy of each rigid body can be calculated according to the speeds of the rigid bodies; superposing the kinetic energy of all the rigid bodies to obtain the total kinetic energy of the whole quasi-static cable rod system; the total kinetic energy of the system should tend to be zero due to the steady state time domain; judging whether the total kinetic energy of the system at the current moment is smaller than a preset kinetic energy threshold value or not; if the total kinetic energy is greater than the threshold value, entering the next time step to continue iterative computation; if the total kinetic energy is smaller than the threshold value, the system is in a static state, and the iterative computation converges; finally, a quasi-static cable steady state potential solution meeting the kinetic energy convergence condition is obtained; and the accuracy of the static equilibrium solution is ensured through the dynamic energy convergence judgment and stabilization iteration process. By means of kinetic energy convergence conditions, whether static iterative computation of a steady state time domain reaches convergence stability or not is effectively judged, and therefore accuracy of a quasi-static cable-rod steady state potential solution is guaranteed.

Calculating the total kinetic energy of the system at each time step, and judging whether a preset convergence tolerance is reached or not; meanwhile, judging the difference between the total kinetic energy of the system at the current moment and the previous moment; if the total kinetic energy does not meet the tolerance requirement and the current value is larger than the previous time value, entering the next time step to continue iteration; if the total kinetic energy reaches the tolerance requirement or the current value is smaller than the previous time value, finishing iteration; comprehensively judging the kinetic energy absolute value convergence condition and the kinetic energy variation trend condition; repeating the dual convergence judgment until two conditions are met simultaneously, and ending the steady-state iterative computation; finally, the configuration value solution of the quasi-static cable pole under the steady state is obtained; by means of double judgment of absolute kinetic energy convergence and change convergence, steady iterative calculation is more stable and reliable. The method reasonably adopts double judgment conditions of kinetic energy absolute value convergence and variation convergence, and ensures the calculation accuracy of the quasi-static cable-stayed steady state potential solution.

In summary, the present application describes the large deformation nonlinear dynamic response of the cable system by using the finite rigid body method, adopts the central differential format in numerical calculation, and solves the dynamic parameters of each rigid body through iterative convergence. The method has the technical effect that the calculation precision of the large deformation motion of the cable rod is improved. The system comprises a rigid discrete module, a connection unit definition module, a time domain interval division module, an unsteady state time domain calculation module, a steady state time domain calculation module, a direction vector calculation module, a dynamic equation calculation module and a convergence judgment module. The cable rod system is discretized into rigid bodies, rigid-flexible connection units are defined, the motion process is divided into an unsteady state interval and a steady state interval, and different solution ideas are adopted in the two intervals. And performing kinematic forward solution in an unsteady state interval, and performing static balance inverse solution in a steady state interval. And (3) iteratively calculating the dynamic parameters of the rigid body by using a central differential format, and determining the accuracy of the solution through kinetic energy convergence. Compared with the existing methods such as a spring rigid body method, the method and the device consider the axial rigidity of the cable rod, and can describe the motion rule of the cable rod more accurately. The calculation accuracy is improved by adopting non-uniform rigid body distribution, and the iteration convergence processing ensures the stability of knowledge. The method can be widely applied to dynamic numerical calculation of large-deformation nonlinear cable rod systems such as hoisting machinery, bridge frame systems and overhead travelling crane hoisting.

In some embodiments of the present disclosure, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In some embodiments of the present disclosure, however, the computer-readable signal medium may comprise a data signal propagated in baseband or as part of a carrier wave, with the computer-readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer storage medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer storage medium may be transmitted using any appropriate medium, including but not limited to: electrical wires, fiber optic cables, RF (radio frequency), and the like, or any suitable combination of the foregoing.

The computer storage medium may be included in the electronic device: or may exist alone without being incorporated into the electronic device. The computer storage medium carries one or more programs that, when executed by the electronic device, cause the electronic device to perform the method of resolving a cable of the present application.

Claims (9)

1. A nonlinear dynamic finite rigid body method for resolving time domain characteristics of a cable-rod system, comprising:

discretizing the cable rod system into a plurality of rigid bodies, wherein the rigid bodies comprise connecting units and driving units;

dividing a continuous driving motion process into an unsteady time domain interval and a steady time domain interval according to the motion time domain characteristics of the cable rod system;

setting the initial speed of a driving unit in the acquired unsteady time domain interval, and performing kinematic positive solution calculation to obtain a displacement solution of the rigid body;

setting the initial length of a driving unit in the acquired steady time domain interval, and performing static equilibrium inverse solution calculation to obtain a displacement solution of the rigid body;

calculating the direction vector of the connecting unit according to the results of the kinematic solution and the static equilibrium solution by adopting a particle method;

calculating the displacement, the speed and the acceleration of the rigid body by adopting a dynamics method and combining the acquired direction vector of the connecting unit;

according to the obtained displacement, speed and acceleration of the rigid body, calculating and judging whether the total kinetic energy of the system is converged or not, and using the total kinetic energy as a convergence criterion for kinematic calculation;

setting the initial speed of the driving unit in the acquired unsteady time domain interval, and performing kinematic positive solution calculation to obtain a displacement solution of the rigid body comprises the following steps:

Setting the initial speed of a driving unit as an initial condition of kinematic solution in an unsteady time domain interval;

dividing the time of the unsteady time domain interval into a plurality of time steps, and calculating the driving displacement of the driving unit according to the set initial speed in each time step;

calculating the internal force of the driving unit in the current time step according to the driving displacement of the driving unit in the current time step and according to the internal force displacement relation in the pre-established rigidity matrix of the driving unit;

integrating unbalanced forces born by the rigid bodies in the current time step according to the internal forces calculated by the connecting units in the current time step;

calculating the displacement, the speed and the acceleration of each rigid body in the current time step by adopting a central difference method according to the unbalanced force of each rigid body in the current time step;

calculating the kinetic energy of the rigid body and the total kinetic energy of the system according to the speed of each rigid body in the current time step;

judging whether the total kinetic energy of the system meets a preset convergence condition, if not, entering the next time step to continue iterative computation until the convergence condition is met.

2. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 1, wherein:

According to the driving displacement of the driving unit in the current time step and according to the internal force displacement relation in the pre-established driving unit stiffness matrix, calculating the internal force of the driving unit in the current time step comprises the following steps:

establishing a local coordinate system between two end point rigid bodies of the driving unit;

under the established local coordinate system, calculating the axial strain of the driving unit at the current time step by utilizing the axial strain and axial displacement relation of the driving unit according to the material parameters, the section parameters and the driving displacement of the end point rigid body at the current time step of the driving unit;

the axial strain of the driving unit is brought into a one-dimensional constitutive equation of the material, and the axial stress of the driving unit at the current time step is calculated;

according to the sectional area of the driving unit, converting the axial stress into the axial tensile force applied to the driving unit at the current time step, namely the internal force of the driving unit;

the calculated internal force of the drive unit is stored in a scalar matrix of force values.

3. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 1, wherein:

the dynamic method is adopted, and the obtained direction vector of the connecting unit is combined, so that the displacement, the speed and the acceleration of the rigid body are calculated, and the method comprises the following steps:

Establishing a differential equation representing the motion of each rigid body by applying an explicit central differential format;

substituting the unbalanced force of each rigid body in the current time step into a differential equation;

assuming an initial displacement and velocity of each rigid body at a current time step;

solving a differential equation to calculate the displacement, the speed and the acceleration of each rigid body at the current time step;

judging whether the calculation result of each rigid body displacement is smaller than a preset displacement tolerance, and judging whether the calculation result of each rigid body speed is smaller than a preset speed tolerance;

if the displacement or the speed does not meet the respective tolerance requirement, updating the initial displacement of each rigid body by adopting the calculated displacement, updating the initial speed of each rigid body by adopting the calculated speed, and returning to the step of solving the difference equation to continue iterative calculation;

if the displacement and the speed meet the tolerance requirements, recording the displacement, the speed and the acceleration of each rigid body in the current time step;

and calculating the total kinetic energy of the system according to the speed of each rigid body, and carrying out kinetic energy convergence judgment.

4. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 1, wherein:

setting the initial length of the driving unit in the acquired steady-state time domain interval, and performing static equilibrium inverse solution calculation to obtain a displacement solution of the rigid body comprises the following steps:

Setting the initial length of a driving unit as an initial condition for static balance calculation in a steady-state time domain interval;

dividing the steady-state time domain interval into a plurality of time steps, and calculating displacement, speed and acceleration in each time step;

calculating the total kinetic energy of the system according to the speed obtained by iterative calculation of each rigid body in the current time step;

judging whether the total kinetic energy of the system reaches a preset convergence tolerance;

continuously judging the difference between the total system kinetic energy of the current time step and the total system kinetic energy of the last time step;

and when the total kinetic energy of the system does not reach the set tolerance and is larger than the previous time step value, entering the next time step to continue the static balance iterative calculation.

5. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 4, wherein:

dividing the steady state time domain interval equally into a plurality of time steps, calculating the displacement, velocity and acceleration in each time step comprises the steps of:

calculating the displacement of the driving unit in the current time step according to the set initial length;

bringing the displacement of the driving unit into an internal force displacement relation equation of each connecting unit, and calculating the internal force of each connecting unit in the current time step;

Substituting the internal force of each connecting unit into a dynamic equation, and adopting a central difference method to iteratively calculate the displacement, the speed and the acceleration of each rigid body in the current time step.

6. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 1, wherein:

discretizing the cable system into a plurality of rigid bodies comprises the following steps:

according to the stress state of the cable rod, acquiring the front N-order vibration modes of the cable rod by adopting a modal analysis method, and generating each-order vibration mode curve;

densely distributing rigid bodies at the wave crest and the wave trough of each order of vibration mode curve by adopting a distance smaller than the minimum distance between adjacent rigid bodies;

adopting a spacing dispersion distribution rigid body larger than the maximum distance between adjacent rigid bodies in the waveform straight section of each order vibration mode curve;

setting the distance between adjacent rigid bodies, and setting the minimum distance between the rigid bodies at the position with the maximum curvature of each order vibration mode curve; at the minimum curvature, the rigid body spacing is set to be the maximum.

7. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 1, wherein:

setting a connecting unit between the rigid bodies, wherein the connecting unit comprises: the device comprises a rigid beam unit connected with a rigid body without rotation constraint release, a rigid two-force rod unit connected with the rigid body with rotation constraint release, a rigid linear cable unit and a curve cable unit, wherein the rigid linear cable unit and the curve cable unit are connected with rigid bodies between cable rods.

8. The nonlinear dynamic finite rigid body method for resolving the time domain characteristics of a cable system according to claim 1, wherein:

the initial speed of the driving unit is a constant speed or a variable speed;

the constant speed represents that the initial speed of the driving unit in the unsteady state time domain interval is kept unchanged;

the variable speed means that the initial speed of the drive unit in the unsteady time-domain interval changes with time.

9. A system based on the nonlinear dynamic finite rigid body method of resolving the time domain characteristics of the cable system according to any one of claims 1 to 8, comprising:

the rigid body discrete module is used for dispersing the cable rod system into a rigid body according to modal analysis;

the connecting unit definition module is used for setting connecting units and driving units between the rigid bodies;

the time domain interval dividing module is used for dividing a continuous driving motion process of the cable rod system into an unsteady time domain interval and a steady time domain interval;

the unsteady state time domain calculation module is used for carrying out kinematic positive solution calculation in an unsteady state time domain interval;

the steady-state time domain calculation module is used for carrying out static balance inverse calculation in a steady-state time domain interval;

the direction vector calculation module calculates the direction vector of the connecting unit by adopting the rigid coordinate position;

the dynamic equation solving module generates a dynamic equation according to the topological relation of the cable rod system, brings the direction vector of the connecting unit into the dynamic equation, and adopts a central difference method to iteratively solve the motion parameters of each rigid body;

And the convergence judging module is used for judging whether the total kinetic energy of the system meets the convergence condition according to the kinematic calculation result of the rigid body.